The present invention relates to a flow-through cell for the treatment of liquid streams using electrochemical liquid treatment (electrolysis) and, in particular, to a treatment cell having a modular plate design readily adapted to different flow rates. Liquid treatment may include disinfection or oxidation of biological or chemical species, or other use for which electrolysis is appropriate, such as electroflocculation or electrowinning. Electrolysis includes but is not limited to methods using direct current, alternating current, switched direct current, or pulsed power.
Electrochemical liquid treatment systems have been used in a variety of industries for different applications. Chlorine gas and caustic soda are produced commercially by the electrolysis of highly concentrated salt water solutions (brine). Other systems electrolyze brine to produce hypochlorite, and this stream is then injected into another liquid to provide disinfection. Related systems may be used to directly disinfect low salinity swimming pool water as a replacement liquid chlorine disinfecting solutions.
In most cases this electrolytic treatment takes place in a flow-through treatment cell that in its simplest form is a housing with a liquid inlet and outlet, and containing two electrodes, one of which is an anode and the other a cathode. In most cases low voltage DC power is applied, but sometimes the polarity may be switched every several hours to help prevent electrode fouling. A new process provides for AC or switched DC electrochemical treatment. This invention applies to all such methods of electric power.
Until now most of these designs consisted of two or more electrodes, usually flat plates arranged in a stack with insulated separators between them. The housing was a separate shell containing one or more plate stacks and the liquid treatment volume. Flow rates and treatment volumes were limited to selected standard models or required custom fabrication. Little attention was placed on the cleanability and sanitation of the internal flow chamber and the electrode components, preventing its use in applications such as food, beverage and pharmaceutical processing.